Okay, so in order to get by until I get to buying a true macro (I would only get like a 100mm since I would use it mainly for bugs, so it is a bit $$), I would like to mess around with reverse lens macro. Note: I have tested this a bit, so I know I won't get really any pro shot from this, but it seems enjoyable enough

okay, so my lenses are minolta 50 1.7, tamron 70-300mm di, and 18-70mm kit lens.
So which combo would work best? I am going to get the converter rings so I can use a tripod, but I need to decide which is best.

The combos somewhat vary: this person says prime on body with reverse kit, this says tele on body with reverse prime. So would one offer more magnification but one more telephoto? Since this could only be used in a set up (with a tripod etc) I guess I would want more magnification.

Also, will any set up have that "shot through a hole" look like this (so i'd always be cropping a lot)?
Note: not my image

Finally, since there are a lot of old lenses out there, what would decent manual focus macro lens I could get for like $15 on eBay (it just needs to be fastish and have an aperture arm)? that would be easy to attach with another lens and get microscopic macro!

This is all just for fun so don't worry about needing to answer all my questions. Just any tips would be great!

From my limited experience with trying this, I would guess that you are going to get vignetting with almost any combination you use. Least would probably be with tele on body, as the FOV is narrower. There is also less to fiddle with, with the prime on the end.
I think I would just invest in a set of close-up diopter lenses, if this was an area I wanted to pursue. They just screw in the filter ring, and you can stack them for some pretty good magnification.

From my limited experience with trying this, I would guess that you are going to get vignetting with almost any combination you use. Least would probably be with tele on body, as the FOV is narrower. There is also less to fiddle with, with the prime on the end.
I think I would just invest in a set of close-up diopter lenses, if this was an area I wanted to pursue. They just screw in the filter ring, and you can stack them for some pretty good magnification.

brian

Brian's correct. I attempted the reverse lens trick... with several lenses and always got vignetting. Have you thought about a Raynox DCR-250 or DCR-150?

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Gary ---- "The best camera is the one you have with you."<><~~~~~~~~~~~Pentax K-70 ~ Panasonic FZ1000 My Gallery

When a lens is mounted to a camera in the conventional fashion, the objective lens is large, letting in a lot of light. When a lens is reversed on the camera body, the objective lens is quite a bit smaller, letting in significantly less light and requiring slower shutter speeds.

Since the lens won't be talking to the camera, the camera won't know how much to compensate for camera shake, and it won't AE or AF, so you'll need to use M Mode (maybe A Mode, if your model camera can handle it), turn off Anti-Shake and you must use a tripod.

None of the lenses you've got is particularly good, and there's no way to know how well a reversed lens will do ahead of time.

I suggest you skip the reversing rings and go with extension tubes. They cost slightly more (new) than reversing rings, but they will work with any lens, they'll AF and AE, they'll let in more light so the shutter speeds will be faster, and you can use them on a true 1:1 macro lens to make it 1.5:1 or 2:1. (You'll still need to turn off the Anti-Shake though.)

I've done a bit with reversed lenses in front of other lenses but am no expert. From what I've been told, the wider the lens, the more magnification you get when the lens is reversed. So reversing the telephoto in front of another lens wouldn't get you as much as reversing a 50mm in front of a telephoto lens.

You really need two sharp lenses to get good results (all that glass in front of the sensor). You also will have a very small dof. I don't think you'd be very happy with the results from using a zoom lens.

Here are a couple of pictures I did. The lens I had mounted on the camera is a 135mm lens that is very sharp but poorly rated (no coatings, low contrast) - it was originally one of two kit lenses I bought in 1980.

A dime taken by the 135 alone (somewhat cropped and resized):

I used to have an old 2x teleconverter that was very poor quality. I took out the glass and made it into an extension tube. This picture is full frame, resized to fit here. The extension tube (as you can see, mine didn't cost anything) allows you to focus closer than the lens would normally, and since there's no extra glass, you have the same quality that the lens would have on its own. This is a good way to go.

I then reversed a 50mm f1.4 lens in front of the 135 lens. It does give me more magnification than the extension tube, but you can see as you get closer, you start running into depth of field issues.

Now if you want to get into even more magnification, here's a picture with the extension tube and the 50mm reversed in front of the 135 lens:

To give you an idea of just how unwieldy this set-up is, here's what it all looked like. A tripod is an absolute must and your results for anything other than perhaps flat objects like a coin will be low because of the tiny dof.

The other thing I noticed when playing around with reversing lenses - the focus distance of the lens mounted on the camera doesn't mean all that much - the 135 I used had more magnification than the 105 macro lens (that's a true 1:1 lens) I also experimented with.

There is focus stacking software, such as the free Helicon filter, which is supposed to allow you to take several exposures at different focal distances, and add them to get more DOF. Haven't tried it, but maybe when I get more spare time.

Forgot one more thing - each time you add an extra element, you lose light (think of being in a dark tunnel, the further away from the opening you go the less light there is). So a flash is a must. And since many times the lens combination will stick out further than the on-board flash can reach, it generally means an external flash. The pictures I took were taken with a hot-shoe mounted flash.

Good point about adding dof with software. CS4 and 5 have that capability and I've played around with that a bit. Works reasonably well but isn't fool-proof, I've occasionally had to go back through the layers to find the sharpest one then change the layer mask on the others to make sure it shows through when the program has chosen the wrong layer to expose for some reason. I think Helicon is supposed to be better, but I've never tried it.